Ellipse-forming compass



1962 R. M. O'MALLEY 3,065,544

' ELLIPSE-FORMING COMPASS Filed June 12, 1961 ATTORNEY R m w W.

05527 M U/WALLE) 15, $012M 3,065,544 Patented Nov. 27, 1962 3,065,544 ELLWSEFORMTNG CGMPASS Robert M. OMalley, 3&8 W. Hawthorne St, Giendale 4, Calif.

Fiied June 12, 1961, Ser. No. 116,569 11 Claims. {C1, 3327) This invention relates to a compass for forming and drawing ellipses.

An object of the present invention is to provide an instrument of the character described that is manipulated in the ordinary way that circle-forming compasses are manipulated, thereby greatly facilitating the forming of ellipses.

Another object of the invention is to provide an ellipseforming compass that is adjustable to form ellipses varying in the proportion of long to short axis, thereby enabling forming a wide range of differently proportioned ellipses.

A further object of the invention is to provide an ellipseforming compass that is complete in itself, i.e., the same does not require nor depend for its operation upon interchangeable elements, such as templates, but rather requires a simple setting adjustment to enable its use to describe ellipses of predetermined size and long and short axis ratio.

This invention also has for its objects to provide such means that are positive in operation, convenient in use, easily installed in a working position and easily disconnected therefrom, economical of manufacture, relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction and novel combinations and arrangements of parts, which will more fully appear in the course of the following description, and which is based on the accompanying drawing. However, said drawing merely shows, and the following description merely describes, one embodiment of the present invention, which is given by way of illustration or example only.

In the drawing, like reference characters designate similar parts in the several views.

FIG. 1 is a front elevational view, partly in section, of an ellipse-forming compass according to the present invention.

FIG. 2 is a broken front view showing the upper portion of one side of said compass.

FIG. 3 is an enlarged and broken sectional view of the compass parts as in the upper portion of FIG. 1.

FIG. 4 is a similar view of the portion shown in FIG. 3 in another position.

FIG. 5 is a perspective view of an ellipse-forming template used in the present invention.

FIG. 6 is a broken elevational view showing a portion of one of the compass arms as seen from the side thereof directed toward the other compass arm.

The instrument for forming ellipses that is illustrated in the drawing comprises, generally, a bow spring 14 a spinner 11 affixed to said spring, a scribing compass leg 12 and a companion leg 13 connected by the spring 10, a torsion bar 14 extending axially through the leg 13, a compass point member 15 at the end of the bar 14 that extends from the lower end of the leg 13, an ellipse- .forming template 16 slidably, non-rotationally carried by the upper end of the bar 14, and an adjusting nut 17 on said bar 14 and operatively engaged with the template .16 to adjust the position thereof according to the axis ratio of the ellipse desired to be described by the compass. I

its intermediate portion 21 where a screw seat 22 is provided, the same is generally conventional of the bow springs used in spring bow compasses.

The spinner 11 is also typical in that the same extends radially from the tapped seat 22 and comprises a means by which the compass may be manipulated to describe an ellipse much like a conventional compass is manipulated to describe a circle. In this case, said spinner is provided with an axial bore 23 open to the interior of the spring 10.

The scribing compass leg 12 comprises a bar 24 having a pivot 25 with a folding bar 26 extending from said pivot, and a scribing extension 27 on bar 26. The latter, in the usual way, may be separably connected at 28 to the bar 26 and be provided either with a pencil point 29, as shown, or a pen point. It will be noted that the pivot 25 is so located as to provide leg 12 with a wide range of folding adjustability to bring the scribing point 29 nearer or further from the compass point 15, according to the size of the ellipse desired to be scribed.

The above-described leg 12 is provided with an arm 3i) that comprises an integral extension of the bar 24, said arm being directed at an angle to said bar so as to provide the leg 12 with a fulcrum area 31 in which, as shown in FIG. 6, are provided spherical seats 32 for legfulcrumming balls 33. The arm 30 is preferably flat in the manner shown. On the side opposite to the fulcrum area 31 and in the lower portion of the arm 30 is provided a seat 34 into which an end 20 of the bow spring 10 is fitted.

The companion compass leg 13 comprises a tubular bar 35 that has an arm 3th a fulcrum area 31, spherical seats 32, and a seat 34, as above described in connection with the scribing leg 12.

As shown, the bow spring 10 biases the legs 12 and 13 with the bias applied to the lower portions of the arms 30, thereby causing the opposite ends of said legs to spread apart. The bore 36 in the leg 13 is a through cylindrical bore which, at its upper end, opens through the inner face of the arm 30 of said leg 13.

The torsion bar 14 comprises an elongated intermediate portion 37 that is cylindrical and, therefore, has rotational engagement in the cylindrical bore 36 of the leg bar 35. Where the portion 37 extends from the lower end of bar 35, a reduced and, therefore, flexible neck 38 is provided, the same serving as a flexible, yet torsion-resisting, means that connects the bar portion 14 and the compass point member 15.

The torsion bar 14 includes an upper extension 39 of polygonal cross-sectionhere shown squarea threaded extension '41) on the end of extension 39, and a preferably reduced round extension 41 on the end of the threaded extension 4 Extension 41 rotationally resides in the bore 23 of the spinner 11. A reduced, torsion-resisting and flexible neck 42 connects the bar portion 37 with the square extension 39, the neck being located where the bore 36 ends in the arm 30. Thus, the bar 14 is able to flex at an obtuse angle that is formed between the portion 37 in the leg 13 and the portion comprising the extensions 39, 4t? and 41.

The compass point member 15 comprises a body part 43 that forms an extension of the bar 14 from the flexible neck 38, and at least two spaced pins 44 that extend integrally downward from said body and are adapted to piece a surface so as to hold said member 15 non-rotationally connected to such surface. Three or more pins 44 may be provided, if desired, the intent being to hold the member 15 in fixed position during manipulation of the compass to describe an ellipse.

The template 16 comprises a member having a substantially circular end 45 and an opposite oval end 46,

soonest the member, between said ends, having a transitional form between round and oval. It will be clear that, from the template end 45 to the end 46, the successive cross-sectional planes will be ellipses that having decreasing short diameters with long diameters of constant size. A poly,,- onal bore 47 in said template conforms to the sectional shape of extension 39. Hence, said template 16 is slidingly but non-rotationally carried by said extension.

The adjusting nut 17 has threaded engagement with the extension 4% of the torsion bar 14 and is in flatwise engagement with the end 45 of the template, since the bow spring biases the arms 34% toward each. other and into opposite engagement with the template, thereby pressing said template toward and into engagement with said nut 17. It will be clear that the adjustment of said nut controls the spread of legs 12 and 13 due to the controlled spread of the arms 3% of said legs.

A comparison of FIGS. 3 and 4 reveals that the spread of the legs 12 and 13 is greatest when the arms 3% are in contact with narrower. portions of the template, as in FIG. 3 and least when said arms are in contact with the widest part of the end so of the template, as in FIG. 4. Therefore, when the pins 44 are set on the intersection of the two axes on which an ellipse is to be scribed, with the arms in contact with the narrow part of the template, and the Spinner ii. is manipulated to cause the entire instrument to turn around themember 15, except that the torsion bar 14 will flex at necks 38 and 42, neither said bar nor the template will turn, thereby causing said arms 30 to traverse the surface of the template. It will be clear that a 90 turn of the instrument will cause a traversal of said arms from the position of FIG. 3 to that of FIG. 4 and a gradual contraction of the legs from their spread condition to a narrower spread. Thus, the point 29 will scribe one-quarter of an ellipse from one end of the long diameter thereof to one end of the short diameter. Then, as the instrument is turned through the next 270, the point 29' will successively scribe the remaining three-quarters of the ellipse.

It will be seen that the tubular leg revolves around the portion 37 of the bar 14 and that a small amount of flexure occurs at the necks 38 and 4-2 as the instrument is turned through a full 360. It will be evident that the instrument may be turned in either direction and that the scribing operation may be begun at the short or the long axis, as desired.

The pivot in leg 12 enables making different sizes of ellipses with the same adjustment or setting of the template, all of these ellipses having the same axis ratio, as above indicated.

While the foregoing has illustrated and described what is now contemplated to be the best mode of carrying out the invention, the construction is, of course, subject to modification without departing from the spirit and scope of the invention. Therefore, it is not desired to restrict the invention to the particular form of construction illus trated and described, but to cover all modifications that may fall within the scope of the appended claims.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. An ellipse-forming compass comprising a scribing leg, a tubular companion leg, said legs being joined at a fulcrum, each leg being provided with an arm and said arms being oppositely angularly directed, a template disposed between and engaged with said arms, spring means biasing said arms toward engagement with the template and spreading the compass legs accordingly, a rotational bar extending through the tubular leg, at non-rotational compass point flexibly and non-rotationally connected to and extending from one end of said bar, and a polygonally-sectioned extension flexibly connected to the opposite end of the bar, said template having a hole of the same shape as said extension to non-rotationally connect the template and bar extension.

2. An ellipse-forming compass comprising a scribing leg, a pivot intermediate the ends of said leg whereby the latter is foldable on said pivot, a tubular companion leg, said legs being joined at a fulcrum, each leg being provided with an arm and said arms being oppositely angularly directed, a template disposed between and engaged with said arms, spring means biasing said arms toward engagement with the template and spreading the compass legs accordingly, a rotational bar extending through the tubular leg, at non-rotational compass point flexibly and non-rotationally connected to and extending from one end of said bar, and a polygonally-sectioned extension flexibly connected to the opposite end of the bar, said template having a hole of the same shape as said extension to non-rotationally connect the template and bar extension.

3. An ellipse-forming compass comprising a scribing leg, a tubular companion leg, said legs being joined at a fulcrum, each leg being provided With an arm and said arms being oppositely angularly directed, a template disposed between and engaged with said arms, said template having a generally round end and an oval end with the portion between said ends gradually varying in shape between round and oval accordingly, spring means biasing said arms toward engagement with the template and spreading the compass legs accordingly, a rotational bar extending through the tubular leg, at non-rotational cornpass point flexibly and non-rotationally connected to and extending from one end of said bar, and a polygonallysectioned extension flexibly connected to the opposite end of the bar, said template having a hole of the same shape as said extension to non-rotationally connect the template and bar extension.

4. An ellipse-forming compass comprising a scribing leg, a tubular companion leg, said legs being joined at a fulcrum, each leg being provided with an arm and said arms being oppositely angularly directed, a template disposed between and engaged with said arms, spring means biasing said arms toward engagement with the template and spreading the compass legs accordingly, a rotational bar extending through the tubular leg, a non-rotational compass point flexibly and non-rotationally connected to and extending from one end of said bar, said compass point comprising a part provided with at least two pins to penetrate a surface on which the compass is to scribe an ellipse, and a polygonally-sectioned extension flexibly connected to the opposite end of the bar, said template having a hole of the same shape as said extension to n0nrotationally connect the template and bar extension.

5. An ellipse-forming compass according to claim 1 in which means is provided to adjust the position of the template relative to the fulcrum between the legs to, thereby, regulate the spread of the legs.

6. In a compass having a pair of compass legs connected at a fulcrum and spring-biased in a leg-spreading direction, the improvements that comprise a through bore in one leg, an elongated bar rotationally disposed in said bore, a compass point flexibly connected to one end of said bar and extending beyond one end thereof, said compass point being provided with at least two penetration pins to hold the same non-rotational on and relative to a surface, an arm extension on each leg, said extensions being oppositely inclined with respect to each other and inclined relative to the leg on which provided, and a template non-rotationally connected to the other end of said bar and disposed between the arm extensions on the compass legs, said template being formed to vary the angle between the mentioned arm extensions and, therefore, the spread of the compass legs, during rotation of the-compass around said compass point so that the end of the other leg may scribe a figure on the mentioned surface according to the variations of spread of the compass legs.

7. In a compass according to claim 6, a flexible, torsionresistant neck being provided at the connections between the bar and the compass point.

8. In a compass according to claim 6, a polygonallysectioned extension on the bar and slidably mounting the mentioned template.

9. In a compass according to claim 6, a polygonallysectioned extension on the bar and slidably mounting the mentioned template, a flexible, torsion-resistant neck connecting said extension and the bar.

10. In a compass having a pair of compass legs connected at a fulcrum and spring-biased in a leg-spreading direction, the improvements that comprise a through bore in one leg, an elongated bar rotationally disposed in said bore, a compass point flexibly connected to one end of said bar and extending beyond one end thereof, said compass point being provided With at least two penetration pins to hold the same non-rotational on and relative to a surface, an arm extension on each leg, said extensions being oppositely inclined with respect to each other and inclined relative to the leg on which provided, and

a template non-rotationally connected to the other end of said bar and disposed between the arm extensions on the compass legs, said template being formed to vary the angle between the mentioned arm extensions and, therefore, the spread of the compass legs, during rotation of the compass around said compass point so that the end of the other leg may scribe a figure on the mentioned surface according to the variations of spread of the compass legs, and means to regulate the position of the template relative to the fulcrum between the compass legs to vary the ratio of spreading movement of the compass legs, as desired.

11. In a compass according to claim 10,- a sliding mount for the template, said means to regulate the template moving the same along said mount.

No references cited. 

